1. Field of the Invention
The present invention relates to a signal transmission apparatus and method, and more particularly, to an apparatus for and a method of transmitting an optical signal of a graphic signal, by which a graphic signal is converted into a single optical channel and transmitted.
2. Description of the Related Art
Where a high-speed graphic signal is transmitted via an electrical cable divided into several channels, mutual interference occurs due to a mutual influence between channels, skew due to a delay of inter-channel transmission occurs, an increase in the amount of electromagnetic energy radiated via an electrical wire may damage peripheral devices, and the structure of a connector which connects many channels to each other is complicated.
FIG. 1 is a block diagram of a conventional graphic signal transmission apparatus. Referring to FIG. 1, a graphic chip 10 outputs an original parallel graphic signal made up of an RGB 3-channel 24-bit graphic signal, a data enable signal DE, a clock signal and a control signal. A graphic signal transmission unit 11 converts the original parallel graphic signal output from the graphic chip 10 to a serial graphic signal made up of three graphic signal channels R, G, and B and one clock signal channel. A graphic signal reception unit 12 receives the serial graphic signal, restores the serial graphic signal to the original parallel graphic signal, and transmits the restored parallel graphic signal to a display unit 13.
In the prior art, the basic colors R, G and B of graphics are allocated to three channels, respectively, and an electrical shielding device and cable shielding are fundamentally required to reduce radiated electromagnetic energy and interference between channels. In order to achieve impedance matching between the graphic signal transmission unit 11 and the graphic signal reception unit 12, a terminal impedance of the display unit 12 and a computer (not shown) which is a graphic signal generation device must be controlled according to the type of cables. A conventional graphic signal transmission apparatus is weak for long-distance transmission, and a maximum transmission distance of the conventional graphic transmission apparatus is known to be about 5 m.
In the prior art, where the basic colors R, G and B of graphics are allocated to three channels which are communicated via electrical cables, and where a high-speed graphic signal is transmitted, the signal may be distorted by electrical interference between channels and emission of excess electromagnetic energy may improperly influence peripheral devices. Also, an apparatus for compensating for a delay of transmission by channels is indispensable. Thus, an electrical shielding device and cable shielding must be essentially applied to reduce the interference between channels, a delay of inter-channel transmission and the amount of electromagnetic energy generated. Also, the terminal impedances of the display unit 13 and a computer which generates a graphic signal must be controlled according to the type of cables in order to achieve impedance matching of the graphic signal reception unit 12. Furthermore, a conventional graphic signal transmission apparatus is weak for long-distance transmission.